Outbreak history calendar

19 historical outbreak-response milestones organized by calendar date. PHEIC declarations, disease discoveries, vaccine licensures, and major outbreaks — curated from WHO and CDC primary sources. Each calendar date links to its dedicated anniversary page.

January

5
2020 WHO issues first DON on pneumonia of unknown cause in China
30
2020 WHO declares COVID-19 a PHEIC

February

1
2016 WHO declares Zika virus a PHEIC

March

11
2020 WHO characterizes COVID-19 as a pandemic
12
2003 WHO issues global alert on SARS
23
2014 Ebola virus disease confirmed in Guinea

April

15
1976 Hantaan virus isolated and named
25
2009 WHO declares H1N1 influenza a PHEIC

May

5
2023 WHO ends COVID-19 PHEIC 2014 WHO declares the international spread of poliovirus a PHEIC
14
1993 Sin Nombre virus identified at CDC
16
2026 WHO declares Bundibugyo Ebola PHEIC in DRC and Uganda

July

23
2022 WHO declares mpox (monkeypox) a PHEIC

August

8
2014 WHO declares West Africa Ebola epidemic a PHEIC
16
2012 Yosemite National Park hantavirus outbreak
26
1976 Index case of Yambuku Ebola outbreak (Zaire, now DRC)

September

15
1995 Andes virus discovered in Argentina

October

15
2000 Sudan ebolavirus outbreak declared in Gulu, Uganda

November

29
2007 Bundibugyo ebolavirus discovered in Uganda